The present invention relates to a method and circuit arrangement for optimally controlling an air gap between an electromagnetically levitated vehicle and a rail for the purpose of adapting the air gap between the rail and the respective magnet to unknown disturbances to which the vehicle may be exposed or which may be present in the rail system.
German Patent Publications (DE-OS) Nos. 2,112,047 and (DE-OS) 2,446,936 disclose control systems for the controlling or regulating of such vehicles known as electromagnetically levitated vehicles.
The control systems disclosed in the just mentioned references and any other known control concepts which are employed in connection with the control and guiding of magnetically levitated vehicles leave room for improvement. For example, prior to this invention it has been very difficult and in connection with larger vehicles capable of very rapid travel even impossible to satisfy all the desirable requirements. Such requirements include the needed stability of the vehicle in its stationary condition, a satisfactory travelling characteristic on any given or expectable roadway such as a rail system while maintaining a relatively small rated air gap between the levitation magnet and the respective rail and between the guide magnet or magnets and the respective rail while taking into account a given battery or operating voltage.
The predetermined rated air gap in present day systems is smaller than or equal to ten millimeters due to the rated or prescribed maximum power of the entire control system. Especially in connection with larger, rapidly moving vehicles such a rated air gap dimension would cause, in connection with prior art control systems that either the magnets impact on the rails of the rail system or that it is necessary to increase the size of the rated air gap until an operation free of troubles is assured. The impacting of the magnets on the respective rails cannot be tolerated because it results in unpermissibly high structural stresses or loads whereby, for example, individual magnets could even be torn off their mountings.
The rated air gap may also be increased in its size in response to the travelling speed. However, this approach has the disadvantage that even small air gap increases require an enormous increase in the energy necessary for such increase. For example, if the rated air gap width is supposed to be increased by only 20% corresponding to about 2 mm of a normally 10 mm gap width, the power input increases by at least 44%.